1. Technical Field
The present disclosure relates to a method for preparing cathode active materials of lithium batteries and, particularly, to a method for preparing a spinel type lithium manganese oxide cathode active material of a lithium battery.
2. Description of Related Art
Lithium transition metal oxides are currently used as cathode active materials for lithium-ion batteries, such as spinel type lithium manganese oxide (e.g. LiMn2O4), olivine type lithium iron phosphate (e.g. LiFePO4), and layered type lithium cobalt oxide (e.g. LiCoO2). LiCoO2 is a commonly used cathode active material in commercial lithium ion batteries, and has a stable structure and a high capacity. However, the high cost, toxicity, and limited abundance of cobalt are disadvantages of LiCoO2. As a result, alternative cathode active materials have attracted much interest. One promising candidate is spinel LiMn2O4. The spinel LiMn2O4 has the advantages of low-cost, environmental friendliness, good safety, and high abundance, but has disadvantages of low tap density and poor performance at high temperature.
Chinese Patent Number CN1264233C discloses a method for preparing the spinel LiMn2O4. In the method, the spinel LiMn2O4 is formed into sphere morphology to improve the tap density and specific surface area of the spinel LiMn2O4. Further, the stability of the spinel LiMn2O4 at high temperature is improved by a surface modification method.
However, the spinel LiMn2O4 spheres still have a problem of rapidly decreasing capacity at high charge/discharge current rate, which restricts the application of the spinel LiMn2O4 in power batteries.
What is needed, therefore, is to provide a method for preparing the spinel LiMn2O4 cathode active material of lithium battery, which can be used under a relatively high charge/discharge current rate.